Department of Psychology, New York University, New York, NY 10003Department of Linguistics, New York University, New York, NY 10003NYU Abu Dhabi Institute, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
Modality-specific and modality-general representations. Possible flow of information between modality-general and modality-specific representations of both linguistic meaning and referents. Information originates at the top in linguistic form information, i.e., written or spoken words. This input triggers retrieval of meanings, which in turn are used to find referents. Some theories suggest the existence of a “semantic hub” that is involved in processing semantic representations regardless of the modality of their content (Patterson et al., 2007), and others suggest that meaning is exclusively represented in modality-specific brain systems (Pulvermuller, 2013). Both of these theories are potentially compatible with a model in which referents are represented exclusively in modality-specific brain systems (blue and red arrows, respectively). This hypothesis would suggest that the “referents” box at the bottom left can be removed from the diagram, since referential processing is constrained to modality-specific representations.
Design for auditory referential domains. Time proceeds from left to right, with vertical offset indicating elements that differ between conditions. The arrow indicates the target word for analysis. The upper sequence illustrates a trial in which the target word grunt resolves reference, whereas the lower sequence illustrates a trial in which it does not, and reference is resolved by adding the prepositional phrase in the middle. Below the displays, presentation time of each frame is indicated in milliseconds.
Design for visual referential domains. Time proceeds from left to right, with vertical offset indicating elements that differ between conditions. The arrow indicates the target word for analysis. For both trials with noun targets and trials with adjective targets, the upper sequence illustrates a trial in which the target resolves reference, and the lower sequence illustrates a trial in which reference is resolved later in the sentence. Below the displays, presentation time of each frame is indicated in milliseconds.
Full-model ANOVA results. The ANOVA analysis revealed a significant spatiotemporal cluster for the main effect of reference resolution in the medial parietal lobe of the left hemisphere, indicating an activity increase associated with reference resolution starting at 415 ms after target word onset. Top left, Anatomical extent of the cluster, shown on a lateral and a medial view of the left hemisphere. Each source that was part of the cluster at any time point is color coded, indicating the sum of F-values over time, i.e., how much that particular source contributed to the cluster’s mass. Top right, The anatomical region included in the test is indicated in blue; the left hemisphere is shown for illustration, but the test also included the corresponding area of the right hemisphere. Bottom, The time course of activation in the ROI defined by the cluster in response to the target words, shown separately for auditory and visual referential domains for illustration purposes. Time 0 ms corresponds to the onset of the visual presentation of the target word. The time course plots indicate within-subject standard errors. The time region covered by the cluster is indicated with gray shading (415–600 ms).
Test for conjunction of reference resolution in auditory and visual referential domains. Top, Anatomical extent of the cluster, showing for each anatomical source the sum of the t-values over time, i.e., indicating how much each source contributes to the cluster mass statistic (details analogous to Fig. 4). Below, Activation in the ROI defined by the cluster in the different conditions. Left, Schematic depiction of the referential domains for each condition, and a corresponding example target word. Referents are color-coded for clarity of the results only—referents in the visual referential domains that were presented to subjects were always black and white. Middle, Time course of activation in response to the target word presentation in the ROI defined by the spatial extent of the cluster. The time region covered by the cluster is indicated with gray shading. Right, Bar-plots show the average activation for each condition in the spatiotemporal region covered by the cluster. In both time- and bar-plots, variability is indicated with the within-subject standard error.
Results in auditory cortex. A significant cluster indicated an activation increase when reference was resolved to auditory objects. The time course of activation in the ROI defined by the cluster is plotted separately according to the sequential position of the referent in the auditory domain. For each plot, the relevant position of the referent is indicated in the schematic of the referential domain. Other details are analogous to previous figures.